On 19 July, Ireland walked into his solicitor's office in Southend-on-Sea in Essex, and told him that he had been with Spiteri that night. It was he on the picture, but that he was not the killer - he had left Spiteri in his flat with another man. As Robert Ressler says, "That attestation might have worked, except that Ireland's fingerprints matched the one that had been left on the window ledge in the apartment of the fourth victim [Andrew Collier]." As careful as he had tried to be, Ireland made one mistake. Shortly after he and Andrew Collier had returned to Collier's flat, they had heard a noise outside and gone to look out of the window. When Ireland was clearing up after himself later he forgot that he had touched the window ledge. He was charged with Collier's murder on 21 July, and with Spiteri's two days later.
While on remand in prison, Ireland continued to maintain his innocence in prison until 19 August, when he finally decided to confess to all five murders. He told the officials at the prison, "I am the gay serial killer. Tell police I want to confess." And he did. An officer said, "He wasn't off-hand but gave calculated descriptions in a very low-key manner. He showed no emotion." The next day he was charged with the murders of Dunn, Bradley and Walker. He now gave the police a full and frank confession. Before he gave the details of the murders to the police he told them:
"I feel that there is a side to my personality that can only be controlled by my being restricted to a prison regime. I think long-term prison establishments are humane and they take good care of you. I feel I'm okay within this restricted environment. But I feel there are certain sides to my character - especially within the group that I was targeting - that means I may offend again. I want to remove that possibility. I feel there is a certain side of my character - not all of it by any means - but I'm probably sixty to seventy per cent quite a reasonable human being most of the time. However, there is a side of my character that is quite cold and calculating. I feel that because of the confession I am about to make that I face an extensive prison sentence and that will restrict me. That will stop me harming other people. When my case comes to trial any judge worth his salt is going to find me guilty and he will imprison me and by doing so allow me not to offend again for some time. That's all I really wanted to say."
He then went on to emphasise four points in particular:
- He had not been under the influence of drink or drugs when committing the murders.
- Although he had worked as a bouncer at a gay club in Soho, he was not gay or bisexual himself.
- He had not undressed himself, engaged in any sexual activity with the men, or got any sexual thrill out of the murders.
- He had no grudge against gays particularly, they were picked because they were easy targets. "It could easily have been women," he maintained.
Ireland had both given a full confession and - unlike Christie, Sutcliffe, and Nilsen who also did so - pleaded guilty to all charges. There was thus no need for a trial, only the need for a judge to pass sentence. On 20 December, at the Old Bailey, the Number One Court was told by the prosecutor, John Nutting, of Ireland's "exceedingly thorough," "premeditated and meticulously planned" murders. "Indeed," said Nutting, "it would seem this defendant set out to be a serial killer. He told others that in order to be classified, he knew he would have to commit at least four murders." He targeted homosexuals because they were "a vulnerable group" who would readily put themselves in compromising positions.